Water-based carpet cleaning composition and method

ABSTRACT

A water-based carpet cleaning composition containing 10% to 80% by weight of an alkali metal or ammonium salt of sulfonated oleic acid, up to 40% by weight of additional surfactant, up to 10% by weight of water-miscible organic solvent, up to 10% by weight of heavy metal complexing agent, 2 to 30% by weight of resoiling inhibitor, up to 1% by weight of antistatic agent, up to 3% by weight of preservatives, dyes and fragrances, and the balance, water.

BARCKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a low-foaming carpet cleaning composition andto a process for cleaning large-area textile surfaces using thiscomposition.

2. Discussion of the Related Art

Loose and fitted carpets are often cleaned in place using powder-formproducts which are scattered onto the carpets and removed again undersuction after a mechanical treatment. More intensive cleaning is carriedout with water-based cleaning solutions which are applied to the carpetsand subsequently removed together with the soil after a certain contacttime, optionally accompanied by a mechanical treatment. In this case, adistinction is drawn between so-called shampooing, in which a cleaningsolution is first sprayed onto the carpets and worked into the carpetsusing brushes or similar mechanical aids before the carpets aresubsequently freed by suction from the cleaning solution or rather thefoam formed by the mechanical treatment, and the liquid extractionprocess in which the cleaning solution is sprayed onto the carpetthrough a pressure nozzle and, immediately afterwards, is removed fromthe carpet by a suction nozzle a few centimeters behind the lip of thepressure nozzle. In the institutional sector, large-area textilesurfaces, particularly floor coverings or upholstery materials, arecleaned by this process using spray extraction cleaners of the typedescribed, for example, in Swiss patent CH 646 044. Cleaners of the typein question, which have also recently been marketed for carpet cleaningin the home, consist essentially of a storage container holding agenerally aqueous surfactant solution which is sprayed onto the textilesurface to be cleaned through a nozzle via a hose and which penetratesmore or less deeply into the material to be cleaned. The cleaning effectcan be enhanced by a brush arranged at the end of the hose near thenozzle. In the working direction, the nozzle is followed by a suctionunit which transports the used cleaning solution into a dirty watercontainer. To ensure that the dirty water taken in does not overflow,the dirty water container is provided with a float contact which, whenthe container is full, switches off the pumps used to spray the cleaningsolution and to take in the dirty water so that the dirty watercontainer can be emptied. In any cleaning process of this type, thefreedom from foam of the surfactants present in the cleaningcompositions to be used has to meet stringent requirements because thecleaning solutions are sprayed onto the surfaces to be cleaned throughrelatively narrow nozzles and are removed by suction almost immediatelyafterwards. Any foam formed also enters the dirty water container and,through its volume, prevents the holding capacity of the dirty watercontainer from being optimally utilized.

To avoid this problem, the automatic measured addition of defoamers tothe used cleaning solution before it enters the dirty water containerwas proposed, for example, in W. Lutz, Lexikon fur Reinigungs- undHygienetechnik, 3rd Edition, 1985, page 471. This necessitates on theone hand modification of the standard spray extraction cleaner throughthe incorporation of a defoamer injector and, on the other hand, the useof an additional preparation which makes no contribution to the actualcleaning step.

Accordingly, the problem addressed by the present invention was toprovide a low-foaming cleaning composition for carpets which would beparticularly suitable for use in spray extraction cleaners.

DESCRIPTION OF THE INVENTION

This problem has been solved by the use of sulfonated oleic acid in theform of an alkali metal or ammonium salt, more particularly in the formof the disodium salt, as surfactant component in carpet cleaningcompositions. Accordingly, the invention also relates to carpet cleaningcompositions which contain the salts mentioned in conjunction with othercleaning-active substances.

The carpet cleaning compositions according to the invention areessentially water-based concentrates which may be used for carpetcleaning either as such or after dilution with water. They aredistinguished by good cleaning performance coupled with extremely lowfoaming, even under heavy mechanical stressing.

The present invention also relates to a process for cleaning large-areatextile surfaces, particularly carpets, using surfactant-containingaqueous solutions, in which the textile is wetted with the solution and,optionally, mechanically treated, the solution is substantially removedfrom the textile by suction immediately afterwards and, if desired, thetextile is dried, the process being characterized by the use of acleaning solution which has been prepared by dilution of a carpetcleaning composition containing an alkali metal or ammonium salt ofsulfonated oleic acid as surfactant component. The term "immediatelyafterwards" derives from the interval of normally about 1 cm to 15 cmbetween the pressure and suction nozzles where a spray extractioncleaner is used and the speed of normally 0.5 cm per second to 50 cm persecond with which the lips of the nozzles are moved over the textile tobe cleaned and normally signifies a time of generally less than 2seconds and, more particularly, less than 1 second.

The oleic acid derivatives used as surfactant component in accordancewith the invention are neutralized sulfonation products which are known,for example, from GB 1,278,421 and from DE-OS 39 26 344. As describedtherein, they may be obtained by reaction of oleic acid or technicalmixtures containing oleic acid--obtainable from renewable raw materials,more particularly beef tallow, sunflower oil, rapeseed oil or oliveoil--with gaseous sulfur trioxide and subsequent hydrolysis andneutralization with aqueous bases, more particularly solutions of alkalimetal or ammonium hydroxides. Depending on the origin of the technicaloleic acid starting material, the resulting mixtures of alkenyl sulfonicacid/carboxylic acid salts and hydroxyalkyl sulfonic acid/carboxylicacid salts may contain more or less large amounts of salts of saturatedfatty acids and sulfonation products of other unsaturated fatty acidswhich generally do not impair the advantageous effect on the sulfonatedoleic acid in the cleaning compositions according to the invention.Sulfonated oleic acid salts such as these are preferably present in thecarpet cleaning compositions according to the invention in quantities of10% by weight to 80% by weight and, more particularly, in quantities of15% by weight to 50% by weight.

In addition to the alkali metal or ammonium salt of sulfonated oleicacid, the compositions according to the invention may contain otherlow-foaming surfactants which are primarily nonionic and, preferably,anionic surfactants, although it may be advisable in individual cases touse other types of surfactant. Suitable anionic surfactants are, inparticular, those of the sulfate or sulfonate type, although othertypes, such as soaps, long-chain N-acyl sarcosinates, salts of fattyacid cyanamides or salts of ether carboxylic acids obtainable fromlong-chain alkyl or alkylphenyl polyglycol ethers and chloroacetic acid,may also be used. The anionic surfactants are preferably used in theform of the sodium salts.

Particularly suitable surfactants of the sulfate type are the sulfuricacid monoesters of long-chain primary alcohols of natural and syntheticorigin containing 10 to 20 carbon atoms, i.e. fatty alcohols such as,for example, coconut oil fatty alcohols, tallow fatty alcohols, oleylalcohol, or the C₁₀₋₂₀ oxoalcohols and those of secondary alcoholshaving the same chain length. Other particularly suitable surfactants ofthe sulfate type are the sulfation products of the reaction products ofC₄₋₁₂ alcohols alkoxylated with 1 to 12 mol ethylene oxide with1,2-epoxyalkanes which may be obtained, for example, by the processdescribed in DE-OS 37 23 354. In addition, the sulfuric acid monoestersof aliphatic primary or secondary alcohols alkoxylated with 1 to 6 molethylene oxide may be used. Suitable surfactants of the sulfonate typeare the alkane sulfonates obtainable from C₁₂₋₁₈ alkanes bysulfochlorination or sulfoxidation and subsequent hydrolysis orneutralization and the olefin sulfonates obtained from long-chainmonoolefins having a terminal or internal double bond by sulfonationwith gaseous sulfur trioxide and subsequent alkaline or acidichydrolysis of the sulfonation products.

Suitable nonionic surfactants for the process according to the inventionare, in particular, adducts of 1 to 30 mol and preferably 3 to 15 molethylene oxide with 1 mol of a compound containing 10 to 20 carbon atomsfrom the group of alcohols, alkylphenols, carboxylic acids andcarboxylic acid amides. The adducts of ethylene oxide and/or propyleneoxide with long-chain primary or secondary alcohols, such as fattyalcohols or oxoalcohols for example, are particularly important.Surprisingly, however, the known high-foaming oligoglycosides of thealcohols mentioned are also suitable.

These additional surfactants may be present in the compositionsaccording to the invention in quantities of, preferably, not more than40% by weight and, more preferably, in quantities of 5% by weight to 20%by weight.

Although the carpet cleaning compositions according to the inventioncontain water as preferred solvent, water-miscible organic solvents maybe present in small quantities. Solvents such as these include, inparticular, alcohols containing 1 to 4 carbon atoms, glycols containing2 to 4 carbon atoms and the diglycols and triglycols derived therefromand the corresponding glycol ethers. Such solvents are, for example,methanol, ethanol, propanol, isopropanol, tert.butanol, ethylene glycol,propylene glycol, butylene glycol, diethylene glycol, triethyleneglycol, dipropylene glycol, diethylene glycol monomethyl ether,diethylene glycol monoethyl ether, diethylene glycol monopropyl ether,ethylene glycol monobutyl ether and diethylene glycol monobutyl ether.Solvents such as these are present in the compositions according to theinvention in quantities of, preferably, not more than 10% by weight and,more preferably, in quantities of 1% by weight to 7% by weight.

In addition, the composition according to the invention may containother auxiliaries typically encountered in carpet cleaning compositions,including in particular preservatives, resoiling inhibitors, inorganicsalts, antistatic agents, dyes and fragrances. Among the auxiliaries,above all those which are present in the cleaning composition inrelatively large quantities, those types which lead to solid residues onthe carpet after drying are preferred.

The auxiliaries which are intended to prevent resoiling of the carpetare, primarily, water-soluble or water-dispersible polymers which leadto brittle residues rather than films after drying. Correspondingpolymers of acrylic acid and/or methacrylic acid or copolymers thereofwith other ethylenically unsaturated monomers, for example styrene, arepreferably used. The resoiling inhibitors are present in thecompositions according to the invention in quantities of 2 to 30% byweight and, more particularly, in quantities of 5% by weight to 20% byweight.

Quaternary ammonium compounds absorbed by the textile material arenormally used as the substances which impart an antistatic finish to thecarpet. An antistatic effect on the carpet can also be obtained withinorganic salts. The content of antistatic agents such as these in thecleaning compositions according to the invention is preferably no morethan 1% by weight and, more particularly, between 0.01% by weight and0.5% by weight.

The heavy metal complexing agents suitable for use in the compositionsaccording to the invention are primarily aminopolycarboxylic acids andpolyphosphonic acids or salts thereof, for example nitrilotriacetic acidand hydroxyethane diphosphonic acid. Complexing agents such as these arepresent in the cleaning compositions according to the invention inquantities of preferably no more than 10% by weight and, morepreferably, in quantities of 0.5% by weight to 2% by weight.

Preservatives, dyes and fragrances are present in the carpet cleaningcompositions according to the invention in quantities of preferably notmore than 3% by weight, more preferably in quantities of 0.01% by weightto 1% by weight and, most preferably, in quantities of 0.1% by weight to0.5% by weight.

The production of the concentrates according to the invention does notinvolve any difficulties. It may be carried out simply by mixing theconstituents which may be present either as such or in the form ofaqueous solutions.

A ready-to-use cleaning solution may readily be prepared by diluting thecleaning compositions according to the invention with water.

By virtue of the minimal generation of foam and the low stability of thefoam, the composition according to the invention may be used in higherconcentrations in the cleaning process than in conventional processes,so that even heavily soiled textiles can be cleaned in a singleoperation.

A characteristic feature of the process according to the invention isthe composition of the cleaning solution to be used which is obtained bydiluting the carpet cleaning concentrate according to the invention withwater. The cleaning composition according to the invention is preferablyused in a quantity of 5 ml to 100 ml and, more preferably, in a quantityof 10 ml to 20 ml per liter of the final cleaning solution. The pH valueof the ready-to-use solution is preferably in the range from 4 to 12and, more preferably, in the range from 6 to 8.

The process according to the invention preferably uses a sprayextraction cleaner of the type described above. After removal of thecleaning solution, the carpet is dried. This can be done by leaving thecarpet standing in air, which can mean drying times of up to 2 days.However, drying can be accelerated by using air blowers or heaters.

The new cleaning process has particular advantages in the cleaning ofcarpets in place because fitted carpets are not accessible to thecleaning processes for loose textiles. The process according to theinvention has the same advantages in the case of other textiles whichare not readily accessible to a conventional washing process, such aswall coverings and upholstered furniture. Even when applied to loosecarpets, it affords advantages by virtue of its simplicity over the verycomplicated washing processes typically used for such textiles. Theprocess according to the invention is distinguished not only by a goodresult in surface cleaning, but also by a minimal tendency of thecleaned textile towards resoiling. Pretreatment of the textiles to becleaned is not normally necessary. The process is suitable both forcarpets of synthetic fibers, such as polyamide for example, and forrelatively delicate textiles of natural fibers, such as wool forexample.

EXAMPLES Example 1

Preparation of the disodium salt of sulfonated oleic acid

The disodium salt of sulfonated oleic acid used for the production ofthe cleaning composition according to the invention was obtained bysulfonation of a technical oleic acid from beef tallow (composition:70.7% by weight oleic acid, 11.8% by weight linoleic acid, rest otherC₁₂₋₂₀ fatty acids; acid value 200.4, iodine value 98.3) with sulfurtrioxide and subsequent neutralization and hydrolysis. The sulfonationwas carried out in a tubular falling-film reactor of glass (length 110cm, internal diameter 6 mm) which was surrounded by a heating or coolingjacket and which was provided at its head with a feed unit for the oleicacid and with a gas inlet pipe. The oleic acid was introduced at aconstant rate of 550 g per hour. Gaseous sulfur trioxide (produced byheating oleum) was diluted with nitrogen to a concentration of 5% byvolume sulfur trioxide and introduced into the reactor at such a ratethat the molar ratio of olefinic double bonds present in the technicaloleic acid (calculated from the iodine value) to sulfur trioxide was1:0.9. The reaction temperature was kept at 50° C. by the circulation ofwater through the reactor jacket. After leaving the reactor, thereaction mixture was collected in a glass vessel containing 25% byweight aqueous sodium hydroxide and was heated for 2 hours to 90° C. ata pH value of 8 to 9. The required disodium salt (T1) was obtained in aconcentration of 60% by weight in water.

Example 2

The cleaning compositions according to the invention characterized bytheir composition in Table 1 below were produced by simple mixing of theconstituents.

                  TABLE 1                                                         ______________________________________                                        Composition of the cleaning compositions according to                         the invention [% by weight]                                                                    CC1  CC2     CC3    CC4                                      ______________________________________                                        T1                 60     25      20   24                                     7× Ethoxylated C.sub.9/11 alcohol                                                          --     20      --   6                                      (Lutensol ® ON 70; BASF)                                                  C.sub.12/14 alkyl glucoside, degree                                                              --     --      20   --                                     of polymerization 1.4                                                         6× Ethoxylated C.sub.12/14 fatty acid                                                      --     --      --   8                                      (Eumulgin ® Ti 60; Henkel)                                                Li C.sub.8/12 alkyl sulfate                                                                      --     --      5    --                                     (Texapon ® LLS; Henkel)                                                   Sulfated hydroxyether.sup.a)                                                                     --     10      --   8                                      Na nitrilotriacetate                                                                             --     0.2     --   0.8                                    Na tripolyphosphate                                                                              --     --      3    --                                     Poly(methylmethacrylate)                                                                         --     10      --   --                                     (Neocryl ® NH 20; ICI)                                                    Copolymer of acrylic acid and                                                                    --     --      5    --                                     styrene                                                                       (Ubatol ® TR 1138; Stapol)                                                Ethanol            5      --      3    --                                     Propylene glycol monobutyl                                                                       --     10      --   6                                      ether                                                                         Chloroacetamide    --     0.2     0.2  0.2                                    Water, fragrance, dye                                                                            ad 100                                                     ______________________________________                                         .sup.a) Na salt of the sulfation product of the reaction product of           Nbutanol alkoxylated with 10 mol equivalents ethylene oxide with              1,2epoxyoctane according to DE 37 23 354                                 

Example 3

To test the cleaning effect of the process according to the invention, atypically soiled polyamide velvet-pile carpet was cleaned with aqueoussolutions containing 1% by weight of compositions CC1 to CC4 accordingto the invention using a Floordress® SB 2412 spray extraction cleaner.For comparison, corresponding carpet samples were cleaned under the sameconditions with commercial carpet cleaning compositions C1 consisting of25% by weight alkyl polyglycol ether, 3% by weight Na cumene sulfonate,0.2% by weight silicone foam inhibitor, 0.1% by weight preservative,balance to 100% by weight water), C2 consisting of 8% by weight epoxyfatty acid, 5% by weight fatty acid polyglycol ester, 0.3% by weightfragrance, 0.2% by weight preservative, balance to 100% by weight water)and C3 (consisting of 8% by weight alkyl polyglycol ether, 8.5% byweight Na cumene sulfonate, 2% by weight aminotrimethylene phosphonicacid, 1% by weight sodium hydroxide, balance to 100% by weight water).

The machine foaming intensity of the compositions (1=high foaming, 10=nofoam), foam stability (1=very stable foam, 10=very unstable foam) andthe cleaning effect (1=no difference in relation to the uncleanedtextile, 10=satisfactorily clean) and the tendency of the cleaned carpet(1=serious resoiling, 10=no resoiling) were marked by trained examiners.

                  TABLE 2                                                         ______________________________________                                        Evaluation marks                                                                        CC1  CC2     CC3    CC4   C1  C2   C3                               ______________________________________                                        Foaming intensity                                                                         9      8       8    9     7   6    7                              Foam stability                                                                            10     9       9    8     6   6    6                              Cleaning    9      10      9    8     8   9    9                              Resoiling   10     9       8    9     6   6    6                              ______________________________________                                    

We claim:
 1. A water-based carpet cleaning composition comprising 10% to80% by weight of an alkali metal or ammonium salt of sulfonated oleicacid, up to 40% by weight of low-foaming nonionic and anionicsurfactant, up to 10% by weight of water-miscible organic solventselected from the group consisting of alcohols containing 1 to 4 carbonatoms and glycols containing 2 to 4 carbon atoms and the diglycols andtri-glycols derived therefrom and the corresponding glycol ethers, up to10% by weight of heavy metal complexing agent selected from the groupconsisting of aminopolycarboxylic acids and polyphosphoric acids orsalts thereof, 2 to 30% by weight of resoiling inhibitor selected fromthe group consisting of water-soluble or water-dispersible polymers, upto 1% by weight of quaternary ammonium compound antistatic agent, up to3% by weight of preservatives, dyes and fragrances, and the balance,water.
 2. A composition as in claim 1 wherein said salt of sulfonatedoleic acid comprises the disodium salt.
 3. A composition as in claim 1containing 15% to 50% by weight of said salt of sulfonated oleic acid,5% to 20% by weight of said low-foaming surfactant, 1% to 7% by weightof said organic solvent, 0.5% to 2% by weight of said complexing agent,5% to 20% by weight of said resoiling inhibitor and 0.1 to 0.5% byweight of preservatives, dyes and fragrances.
 4. The process of cleaninga carpet, comprising contacting said carpet with a water-basedcomposition containing 10% to 80% by weight of an alkali metal orammonium salt of sulfonated oleic acid, up to 40% by weight oflow-foaming nonionic and anionic surfactant, up to 10% by weight ofwater-miscible organic solvent selected from the group consisting ofalcohols containing 1 to 4 carbon atoms and glycols containing 2 to 4carbon atoms and the diglycols and tri-glycols derived therefrom and thecorresponding glycol ethers, up to 10% by weight of heavy metalcomplexing agent selected from the group consisting ofaminopolycarboxylic acids and polyphosphoric acids or salts thereof, 2to 30% by weight of resoiling inhibitor selected from the groupconsisting of water-soluble or water-dispersible polymers, up to 1% byweight of quaternary ammonium compound antistatic agent, up to 3% weightof preservatives, dyes and fragrances, and the balance, water, andremoving said composition from said carpet.
 5. A process as in claim 4wherein after contacting said carpet with said composition, mechanicallytreating said carpet.
 6. A process as in claim 4 including removing saidcomposition from said carpet by suction.
 7. A process as in claim 4wherein said composition is applied to said carpet in a quantity of 5 mlto 100 ml per liter of cleaning solution.
 8. A process as in claim 4wherein said composition is applied to said carpet by a spray-extractioncleaning apparatus and is removed with said apparatus.
 9. A process asin claim 4 wherein said salt of sulfonated oleic acid comprises thedisodium salt.
 10. A process as in claim 4 wherein said compositioncontains 15% to 50% by weight of said salt of sulfonated oleic acid, 5%to 20% by weight of said low-foaming surfactant, 1% to 7% of saidorganic solvent, 0.5% to 2% by weight of said complexing agent, 5% to20% by weight of said resoiling inhibitor and 0.1 to 0.5% by weight ofpreservatives, dyes and fragrances.